HIGH CVSS 7.2
Published: 2021-04-13

CVE-2021-29439

getgrav grav_admin Security Advisory (CVE-2021-29439)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2021-29439 impacting getgrav grav_admin. Evaluated with CVSS Base Score of 7.2 (HIGH).

Original NVD Description

Source: NIST NVD
The Grav admin plugin prior to version 1.10.11 does not correctly verify caller's privileges. As a consequence, users with the permission `admin.login` can install third-party plugins and their dependencies. By installing the right plugin, an attacker can obtain an arbitrary code execution primitive and elevate their privileges on the instance. The vulnerability has been addressed in version 1.10.11. As a mitigation blocking access to the `/admin` path from untrusted sources will reduce the probability of exploitation.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
High (PR:H)
Administrative credentials required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product getgrav / grav_admin
Affected Versions *
Weakness Enumeration CWE-863

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2021-29439 impacting getgrav grav_admin.

⚡ Nuclei Detection Template (YAML) cve-2021-29439.yaml
id: cve-2021-29439

info:
  name: getgrav grav_admin - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2021-29439 affecting getgrav grav_admin.
    Evaluation: The Grav admin plugin prior to version 1.10.11 does not correctly verify caller's privileges. As a consequence, users with the permission `admin....
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2021-29439
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.2
    cve-id: CVE-2021-29439
    cwe-id: CWE-863
  tags: cve,cve-2021-29439,getgrav,grav_admin,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "grav_admin"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2021-29439.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2021-29439
# Target: getgrav grav_admin | CVSS: 7.2 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2021-29439 (getgrav grav_admin)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against getgrav grav_admin scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2021-29439.sh
# Recommended Remediation & Patching Commands for CVE-2021-29439
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install grav_admin 2>/dev/null || \
sudo dnf upgrade grav_admin 2>/dev/null || \
sudo yum update grav_admin

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i grav_admin 2>/dev/null || rpm -qa | grep -i grav_admin

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2021-29439 in getgrav grav_admin?

Review vendor-specific security notices and update getgrav grav_admin packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2021-29439?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2021-29439?

CVE-2021-29439 is classified with a CVSS 3.1 Base Score of 7.2 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.2
HIGH SEVERITY
CVE ID CVE-2021-29439
Weakness CWE-863
Vendor getgrav
Product grav_admin
Published 2021-04-13
Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H